The hydroformylation reaction involves the addition of a hydrogen atom and a formyl group to the double bond of an olefinic compound. In early applications of this reaction, finely divided active cobalt metal prepared in much the same manner that a cobalt hydrogenation catalyst is made was used as the hydroformylation catalyst. It was soon discovered that cobalt carbonyl, which is formed quite readily by the action of carbon monoxide on an active metallic cobalt catalyst, is the active ingredient in the hydroformylation reaction. The cobalt carbonyl catalysts have been used extensively in the prior art either alone or in combination with various promoter ligands in order to produce aldehydes from olefins.
The major drawback to the use of the prior art catalyst systems, however, has been that these catalyst systems require high temperatures and high pressures for the reaction to proceed. Moreover, when an unsymmetrical olefin is used as the reactant at least two isomeric products, i.e.branched chain and straight chain, are obtained. No general method has been developed in the prior art for the control of the isomeric product composition.
The present invention overcomes these problems present in the prior art. In this regard, the inventive process results in higher conversions, higher yields and faster reaction rates than those disclosed in the prior art. Moreover, the instant invention is particularly selective for the straight chain isomeric product. Finally, the instant reaction proceeds under relatively mild conditions of temperature and pressure. These advantages can result in substantial cost savings in the production of aldehydes.